Single-order soft x-ray spectra with a spectroscopic photon sieve

A single-order diffraction transmission grating named spectroscopic photon sieve (SPS) for soft X-ray region was proposed and demonstrated in this paper. SPS consists of many circular pinholes located randomly, and can realize both free-standing diffractions and the suppression of higher orders. In this paper, the basic concept, numerical simulations, and calibration results of a 1000-line/mm SPS for soft X-ray synchrotron radiation are presented. As predicted by theoretical calculations, the calibration results of a 1000-lines/mm SPS verified that higher-order diffractions could be significantly suppressed along the symmetry axis. With the current nanofabrication technique, SPS could potentially have a higher line density, and can be widely used for synchrotron radiation, laser-induced plasma diagnostics, and astrophysics.